Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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This invention relates to apparatus for removing tires from and
installing tires on wheel rims, and specifically to apparatus for use with
motorcycle wheel rims.
The art is replete with tire changers, some of which have been
especially designed for use with so-called spoked wheels. One example is
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Adams Canadian Patent No. 965,61~. In general such devices have not acnieved
substantial commercial success and in part the reason for this is the strain
that is put on a spoked wheel by the state of the art tire changers. Some
of the prior art devices rely on clamping arrangements having lugs or arms
that extend between the spokes of a wheel mounted for tire removal, these
lugs transferring torsional forces, applied to the tire on removal or
installation, to the spokes, and thus causing damage to the spokes and
consequent misalignment of the wheel from which the tire is being removed.
Some motorcycle wheel manufacturers expressly state in shop
manuals that tire changers are not to be used since damage to the wheels can
result from their use.
The present invention overcomes the disadvantages of the prior art
in a surprisingly simple and economical fashion.
The invention provides a stand for use in supporting a wheel during
; 20 tire removal and installation operations comprising:
; i an upright member;
ii a plurality of radial arms mounted on said upright member and
radiating from a centre;
iii a corresponding plurality of brackets spaced from the centre
on said arms and having surfaces facing radially outward from the centre;
the brackets being radially adjustable toward and away from the centre; one
bracket being mounted on means for forcibly moving it outwardly from the
centre; and a resilient pad on each of the surfaces for engaging the inside
of a spoked wheel rim without engaging spokes thereon; whereby when a spoked
wheel is mounted on the stand, the pads may engage the inside of the rim
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without projecting through the wheel, the pads forcibly engaging the rim and
having a large surface area to distribute pressure evenly to a substantial
area of the rim.
An embodiment of the invention is illustrated in the accompanying
drawings, in which:
Figure 1 is a perspective view of a tire changer constructed
according to the invention;
Figure 2 is a detail view showing the adjustable screw clamping
apparatus used in the structure of Figure 1, and
Figures 3, 4 and 4a are detailed views of the hinge for folding
the structure.
Referring to Figure 1, there is shown a post 10 on top of which
there is mounted a structure 3 comprising three radial arms. The post 10 is
welded to a base 11 that can be secured to a shop floor. A hinge (Figures 3,
4 and 4a) is provided between the structure 12 and the post 10 so that the
apparatus can be folded for easy storage. To the above end, and referring to
Figures 3 and 4, there is provided a hinge 13 between the post 10 and the
structure 12 and a pin 14, to which is attached a ring 14a, that may register
with holes 15 that are aligned when the structure 12 is in its operative
position. The structure 3 is shown, in phantom lines, in Figure 4 as folded
for s~orage.
Welded on top of first and second arms 16 and 17, which are prefer-
ably formed from suitable rectangular section steel tubing, are sections of
like rectangular steel tubing 18 and 19 respectively having drilled therein a
plurality of holes 20 suitably spaced. Metal brackets 21 as shown in Figure
1, are provided for each of the arms 16 and 17 such that the pins 22 secured
in the brackets 21 can register with two of the holes 20 to provide for
adjusting movement of the brackets 21 to accommodate various sizes of wheel
rim.
On the third arm 23 there is mounted a section of rectangular
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steel tubing 25 (Figure 2) having an outer plate 24 welded thereto through
which there is inserted a threaded rod 26 having at its outer end a handle
27. The threaded rod 26 is provided with two collars 28 and 29 (Figure 2),
secured e.g. by cotter pins, one on each side of the outer plate 24 of the
tubing section 25, to prevent axial moveDIent of the threaded rod 26, and a
block 30 which is internally threaded to mate with threaded rod 26 is mounted
within the section 25 and can be moved along the inside of section 25 by
rotating the threaded rod 26 via the handle 27. On the upper surface of the
block 30, and registrable with slot 31, are two threaded holes 32. Into
these holes suitable bolts 32a can be installed whereby a bracket 33 can be
attached to the block 30 for movement of the bracket by rotation of the
handle 27.
On the outer surfaces of the three brackets are mounted resilient
pads 34, facing outwardly, that are intended to engage the inside of a rim,
it being important to note that the blocks are relatively large to provide
for a large surface contact area on the rim to minimize strain thereon. A
suitable size is 3" x 1", and a suitable material is rubber.
In operation, the brackets 21 on the two arms 16 and 17 are, via
the pins 22, installed in holes 20 in the two arms 16 and 17 in the locations
appropriate for the rim size. A wheel is located on the structure, and the
handle 27 is then rotated, moving the bracket 33 on the arm 23 to bring the
pad thereon and the pads on brackets 21 into firm engagement with the inside
of the rim.
It is important to note that the rubber pads described above engage
the inside portion of the rim that is lowermost and do not protrude between
the spokes. Thus, there is only frictional engagement between the three
rubber pads and the vehicle rim. The relatively large area of the pads has
the effect of firmly gripping the rim without applying destructive stress to
the rim or spokes.
3~ After the wheel is secured via the pads, a threaded pin 35 is
inserted through the center of the wheel hub into a threaded hole 36 centrally
disposed at the junction of the three arms. The pin preferably is so shaped
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that it will positively engage at least a portion of the inside of the hub.
The pin is used as a fulcrum for a bead breaking tool of the type known in
the art.
By means of the device described above it is possible to carry out
a tire changing operation with relative ease on a motorcycle wheel without
unduly straining the construction of the wheel and indeed without any positive
engagement between the apparatus and the spokes of the wheel, the avoidance
of contact between the spokes and the apparatus being important to prevent
damage.
